Pick-up for use with record players



J. C. W. DRAGT Filed Feb.

PICK-UP FOR USE WITH RECORD PLAYERS Oct. 1, 1963 INVENTOR 1m c.w.ORAGTAGENT United States Patent 3,105,691 PICKUP FOR USE WKTH RECGRD PLAYERSTan tlornelis Wiilem Dragt, Eindhoven, Netheriands,

assignor to North American Phiiips Company, Inc.,

New York, N,Y., a corporation of Delaware Filed Feb. 9, 1960, Ser. No.7,572 Claims priority, app-iication Netheriands Mar. 26, 1%9 3 *Claims.(iii. 274-65) The invention relates to a pick-up for use in a recordplayer, this pick-up comprising a pick-up unit housed in an envelopewith two diametrically opposite needles, which can be moved into theworking position by turning them about the longitudinal axis of the unitin one direction and in the other direction respectively.

Pick-ups of this kind are generally known and used in practice. The turnof 180 to be performed by the pick-up unit to go over the workingposition of one needle to the working position of the other is limited,in these known devices, as a rule in both directions by stationaryrabbet.

The invention is based on the recognition of the fact that theadjustment of the needle in its working position with stereophonicrecord players is extremely critical, since the cross-talk factor fromone sound channel to the other becomes considerably more unfavourableeven when the pick-up occupies only a slightly oblique position. With adeviation of not more than 2", for example, this factor amounts alreadyto 2.

The invention consists in that the turn of the pick-up unit is limitedon both sides by a stop, of which stops at least one is accuratelyadjustable. less important for the other stop, if it is associated withthe working position of a needle not used for stereophonic reproduction.

The accompanying drawing shows a longitudinal sectional view of oneembodiment of a pick-up according to the invention.

In a housing 1 of light material is arranged a pick-up unit 2 so as tobe rotatable on gudgeons 3, which fit in round openings of a frame 4,secured in the housing. The pick-up unit comprises two diametricallyopposite needles 5 and 6, of which the latter is to be used forstereophonic reproduction and must therefore be movable Thisadjustability is' into its working position with great accuracy and beheld therein. This position is shown in the FIGURE.

The unit 2 can be turned about the gudgeons 3 with "ice the aid of a tag7, which is at right angles to the plane of the drawing and whichprojects, as shown in the drawing, downwardly below the housing 1, andwhich is secured to the unit by a rivet 8.

A flat spring 9, secured to the frame 4, co-operates with a lug-shapedpart it) of the unit 2, which part is provided to this end with twoopposite flat surfaces, of which the surface 11, shown in contact withthe spring, is to some extent oblique to the plane of the drawing, sothat the unit 2, if it were free, would turn slightly beyond the correctposition of the needle 6 under the action of the spring pressure.However, this additional turn is prevented by a screw-bolt 12, locatedbelow the unit 2, as shown in the drawing; this bolt has a finescrewthread. The point of this bolt abuts against the stationary stop 13of the frame 4- as soon as the needle 6 arrives at its correct position.Small deviations from this position may always be corrected by means ofthe bolt 12.

What is claimed is:

l. A phonograph cartridge comprising a housing, a pick-up unit rotatablymounted in said housing and .having two spaced, alternately operatingneedles therein, said pick-up unit being rotatable about itslongitudinal axis to bring the selected needle into record-engagingposition, and at least two stops for limiting the rotation of saidpick-up, one of said stops being provided with means for adjusting thesame whereby the selected needle is located in the correctrecord-engaging position.

2. A phonograph cartridge comprising a housing, a pick-up unitrota-tably mounted in said housing and having two spaced, alternatelyoperating needles therein, said pick-up unit being rotatable about itslongitudinal axis to bring the selected needle into record-engagingposition, and at least two stops for limiting the rotation of saidick-up, said pick-up unit having a relatively fiat, lugshaped part, aspring secured at one end to said housing and the free end thereofcontacting said lug-shaped part when one of said stops engages saidrotated pick-up unit.

3. A phonograph cartridge as claimed in claim 1 wherein said means foradjusting one of said stops is a screw bolt abutting against the otherof said stops.

References Qited in the file of this patent UNITED STATES PATENTS

1. A PHONOGRAPH CARTRIDGE COMPRISING A HOUSING, A PICK-UP UNIT ROTATABLYMOUNTED IN SAID HOUSING AND HAVING TWO SPACED, ALTERNATELY OPERATINGNEEDLES THEREIN, SAID PICK-UP UNIT BEING ROTATABLE ABOUT ITSLONGITUDINAL AXIS TO BRING THE SELECTED NEEDLE INTO RECORD-ENGAGINGPOSITION, AND AT LEAST TWO STOPS FOR LIMITING THE ROTATION OF SAIDPICK-UP, ONE OF SAID STOPS BEING PROVIDED WITH MEANS FOR ADJUSTING THESAME WHEREBY THE SELECTED NEEDLE IS LOCATED IN THE CORRECTRECORD-ENGAGING POSITION.